Ammonites were the ancestors of the modern day Nautilus. They were predatory, squid like and lived inside shells that were coil shaped. Today they are the most widely known fossil, all have a spiral formed shell. Ammonites once roamed the seas in large numbers until becoming extinct with the dinosaurs. These creatures had evolved from small, straight shelled creatures known as bacrites. As evolution kicked in they were changed into many different shapes and sizes.
Today ammonites are being sold for the beauty and phenomenon that these fossils contain, and many collectors can be found around the world.
Scientists use ammonites to see how creatures evolve over time, and what factors are involved in adaptions. The Ancient Guitar Fish also has fossils that were fomr around the same age.
Ammonite Drawings
Scientific Classification:
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Habitat
Map of Jurassic Period
Ammonites lived in the oceans of the Jurassic and Cretaceous periods. The
Jurassic Sea
environment was warmer so the oceans then had a higher temperature than the nautilus is living in now. There isn't much information on the ocean environment at the time but scientists assume it is very similar to today's. Ammonities would have lived in more areas as the sea would have been warmer. They would have lived at the edges of rocks, cliffs, or coral that lead down into the deep ocean.
Ammonites would reside in the dark, deep ocean during the day and rise to the surface when needed to feed. Many would live in the Pacific Ocean as nautiluses do today, but in much larger amounts.
Adaptations Behavioral Adaptations #1: Dark during day Ammonites stayed in the dark waters of the deep sea (less than 100m) during the day to avoid predators. There weren't many dangers at the bottom of the sea for them, and it was hard for other marine creatures to see them in pitch black. This allowed them to be safe and survive. The ammonites were clever in adapting to staying in the dark to avoid the risk of a predator coming by, because their shells weren't very evolved yet and wouldn't be as strong as the one's found on the nautilus today. During the night they would rise to the surface to eat, because it was easier for ammonites to be discrete in the dark rather than light. This routine of being in the dark worked well in keeping them safe from the other marine creatures wanting to make them food.
Squirting ink
Behavioral Adaptations #2: Squirting ink When being attacked by a predator the ammonites would squirt ink to warn and scare off the attacker. However this worked with the smaller enemies but not with the larger ones. By squirting the ink they would be able to have a slight chance of not being eaten, but it still helped to protect them. Another reason the ammonites squirted ink was to blur the attacker's vision enough so that it could go hide or run away. This helped to save alot of ammonites that would have otherwise been eaten. Similar to the octopus.
Structural Adaptations #1: Jet Propulsion Ammonites had a funnel like opening that would expel water to move them in the opposite direction. This was the way they used to move around. This helped ammonites do everything, especially go to the surface to find food and move away from predators. This gave them the control of moving around, rather than having to wait for a certain type of current to push them to where they have to go. The jet propulsion improved their lifestyles which then lead to adaptation that couldn't have been done before. Being able to move around was the most important thing to stay alive.
Structural Adaptations #2: Linked chambers
Linked chambers
The majority of ammonite shells are coiled and contain linked chambers. There was a large chamber at the end of the spiral that was called the living chamber. This is where the tentacles extended to catch prey. When a predator would approach the ammonite would go inside its shell and squeeze into all the different chambers so it is concealed inside. This was a way of hiding if there was a danger. The chambers also contained gasses to help the ammonite regulate its buoyancy, being able to do this would have allowed more control. It could also have helped them stay at a level where the pressure wasn't strong enough to crack their shells.
Physiological Adaptation: Higher metabolism Ammonites had higher metabolisms then because they ate more. Their body adapted to consumption of more food and created a way to burn it faster. This allowed them to have more energy to hunt and prey as they ate more often. The higher metabolism helped to make them stronger in the process of hunting because they had more room for food more often.
Extinction Pressure
The last ammonite families went extinct with the dinosaurs at the end of the Cretaceous period 65 million years ago. They were on a decline in families but the extinction cannot be blamed on natural extinction. One theory that has been brought up was that the shell of the ammonite would not be able to withstand the acid rain that probably followed the vaporization of limestone into the atmosphere which was then followed by a meteor impact. It is uknown what real reason to their extinction was.
"DISCOVERING FOSSILS | What is an ammonite?." DISCOVERING FOSSILS | Introducing the palaeontology of Great Britain. N.p., n.d. Web. 21 July 2010. <http://www.discoveringfossils.co.uk/ammonites.htm>.
"Ammonite - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 21 July 2010. <http://en.wikipedia.org/wiki/Ammonite>.
Fossil Animal Modern Animal Future Animal
Today ammonites are being sold for the beauty and phenomenon that these fossils contain, and many collectors can be found around the world.
Scientists use ammonites to see how creatures evolve over time, and what factors are involved in adaptions. The Ancient Guitar Fish also has fossils that were fomr around the same age.
Scientific Classification:
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Habitat
Ammonites would reside in the dark, deep ocean during the day and rise to the surface when needed to feed. Many would live in the Pacific Ocean as nautiluses do today, but in much larger amounts.
Adaptations
Behavioral Adaptations #1: Dark during day
Ammonites stayed in the dark waters of the deep sea (less than 100m) during the day to avoid predators. There weren't many dangers at the bottom of the sea for them, and it was hard for other marine creatures to see them in pitch black. This allowed them to be safe and survive. The ammonites were clever in adapting to staying in the dark to avoid the risk of a predator coming by, because their shells weren't very evolved yet and wouldn't be as strong as the one's found on the nautilus today. During the night they would rise to the surface to eat, because it was easier for ammonites to be discrete in the dark rather than light. This routine of being in the dark worked well in keeping them safe from the other marine creatures wanting to make them food.
When being attacked by a predator the ammonites would squirt ink to warn and scare off the attacker. However this worked with the smaller enemies but not with the larger ones. By squirting the ink they would be able to have a slight chance of not being eaten, but it still helped to protect them. Another reason the ammonites squirted ink was to blur the attacker's vision enough so that it could go hide or run away. This helped to save alot of ammonites that would have otherwise been eaten. Similar to the octopus.
Structural Adaptations #1: Jet Propulsion
Ammonites had a funnel like opening that would expel water to move them in the opposite direction. This was the way they used to move around. This helped ammonites do everything, especially go to the surface to find food and move away from predators. This gave them the control of moving around, rather than having to wait for a certain type of current to push them to where they have to go. The jet propulsion improved their lifestyles which then lead to adaptation that couldn't have been done before. Being able to move around was the most important thing to stay alive.
Structural Adaptations #2: Linked chambers
The majority of ammonite shells are coiled and contain linked chambers. There was a large chamber at the end of the spiral that was called the living chamber. This is where the tentacles extended to catch prey. When a predator would approach the ammonite would go inside its shell and squeeze into all the different chambers so it is concealed inside. This was a way of hiding if there was a danger. The chambers also contained gasses to help the ammonite regulate its buoyancy, being able to do this would have allowed more control. It could also have helped them stay at a level where the pressure wasn't strong enough to crack their shells.
Physiological Adaptation: Higher metabolism
Ammonites had higher metabolisms then because they ate more. Their body adapted to consumption of more food and created a way to burn it faster. This allowed them to have more energy to hunt and prey as they ate more often. The higher metabolism helped to make them stronger in the process of hunting because they had more room for food more often.
Extinction Pressure
The last ammonite families went extinct with the dinosaurs at the end of the Cretaceous period 65 million years ago. They were on a decline in families but the extinction cannot be blamed on natural extinction. One theory that has been brought up was that the shell of the ammonite would not be able to withstand the acid rain that probably followed the vaporization of limestone into the atmosphere which was then followed by a meteor impact. It is uknown what real reason to their extinction was.
Biliography
Websites:
"Ammonites." Easynet Connect - Quality Business Internet Access. N.p., n.d. Web. 21 July 2010. <http://easyweb.easynet.co.uk/~gcaselton/fossil/ammonite.html>.
"DISCOVERING FOSSILS | What is an ammonite?." DISCOVERING FOSSILS | Introducing the palaeontology of Great Britain. N.p., n.d. Web. 21 July 2010. <http://www.discoveringfossils.co.uk/ammonites.htm>.
"Ammonite - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 21 July 2010. <http://en.wikipedia.org/wiki/Ammonite>.
"Ammonites - ZoomSchool.com." ENCHANTED LEARNING HOME PAGE. N.p., n.d. Web. 21 July 2010. <http://www.enchantedlearning.com/subjects/dinosaurs/glossary/Ammonite.shtml>.
Pictures (in order from top to bottom):
http://skywalker.cochise.edu/wellerr/students/ammonites/6ammonite-laguna.jpg
http://upload.wikimedia.org/wikipedia/commons/d/da/Haeckel_Ammonitida.jpg
Diagram:
http://easyweb.easynet.co.uk/~gcaselton/fossil/ammonite.html
Map:
http://www.dinosaurcollector.150m.com/index_files/LJURASSIC.gif
http://upload.wikimedia.org/wikipedia/commons/d/da/Haeckel_Ammonitida.jpg